Boost control



Feb; 25,1941. y, a Lovzxvrr 5ml.

BOOST CONTROL.-

Filed Feb. 4,` 1937 El?. I

9 Sheets-Sheet 1 W .ffm

ww w@ @OOST CONTROL Filed Feb. v4, 1937 9 Shee'ts-Sheet 2 Feb. 25,1941. vR, QZMT Em 2,233,319

1 BOOST CONTROL l I Filed Feb. 4, -193'7 9 Sheets-Sheet 3 Feb. 25, 1941.

Feb.25,1941. `RQLQZMT AL v2,233,319

BOOS'IIv CONTROL Filed Feb. 4, 1957 9 Sheets-Shes?I 5 Fly. 3

Feb. 25, 1941. R, LOZ|V|T ET'AL 2,233,319

Boos'r CONTROL Filed Feb. 4, 1937 9 Sheets-Sheet 6 Ey] y Feb. 25,V 1941.

R. Lozlvn' rrm.. 2,233,319

BDOST CONTROL Filed Feb. 4, 1937 9 sheets-sheet v ffy/0 Feb. 25, 1941. R. LoZlvlT r- TAL 2,233,319

BOOST CONTROL Filed Feb. 4, 1937 9 SheetsSheet 8 Feb. 25, 1941. n. LOZlVlT HAL BOOST CONTROL Filed F'eb.l 4L 1937 9 Sheets-Sheet 9V Pienaar-ea 2 5, 1941 oui-'riso srArss Fureur sor-Fien vallois-Perret, and

yPaul Xavier Auguste Gistucci, Paris, France, assignors to Societe Generale Des Carburateurs Zenith,

Switzerland Geneva,

Appueanmrebmary 4, 1931, serial No. 124,149

- ra Belgium February 11, 193s 17 Claims.

The present ihvention relates to the control of the amount 'of air or mixture supplied to an engine having a boost control. y

An object of-the invention is to eliminate the lost motion which frequently occurs in the pilots throttle control, when the induction pressure is controlled by a boost control. Another object of the invention is an improved boost control unit. n

Another object of the invention is an improved combined control of a. throttle valve by the pilots throttle lever and by the boost control.

Another object of the invention is to provide an engine in which the maximum' permissible inducw tion pressure, as adjusted by the boost control,

isvaried according to the altitude.

Other objects of the invention will appear from the following description in connection with the appended drawings, whereinzgn Fig. i. illustrates schematically, in elevation, the intake manifold of 'an engine provided with a compressor, a carburettor and a control device according to the invention.

Fig. 2 illustrates schematically in longitudinal g5 section .the boost control forming ,part of the control device illustrated in Fig. 1.

Figs. 3 to 5 illustrate schematically, in longitudinal section, modifications of the boost control illustrated in Fig. 2.

le Fig. illustrates schematically, in elevation, a modification of the device illustrated in Fig. i, including the boost control unit shown'in Fig. 5. Fig. 6 illustrates schematically, inlongitudinal section, a further'modication of the boost con- 35 trol shown in Fig. 2. A

` Fig. 7 illustrates schematically, in elevation, a

further. modication of, the device illustrated in Fig. i, and l Fig. il illustrates schematically, in longitudinal section the boost control of the device illustrated in F18. 7'.

Fig. 9 illustrates schematically, in elevation, an arrangement in which two distinct throttle valves are employed and controlled respectively by the boost control and by the pilots lever.

Fig. l0 illustratesfschematically, in partial sectional elevation, another form of construction oi the invention in which the boost control controls a device for regulating the speed oi a compressor disposed in the intake manifold of the engine.

Fig. li illustrates a section along' of a detail oi the device illustrated in Fig. 3.

Fig. l2 illustrates schematically, in elevation, a method oi carrying out the invention, in which. the chamberoi the boost control which contains the manometric element is connected to the intake v [A manifold between the regulating device controlied by the boost control and the throttle valve controlled by the pilot. v

Figs. 13 and. i4 illustrate, in longitudinal sec- 5 tion, variations in the construction of 4the boost control illustrated 'in Fig. 2.

In the figures, the same reference numerals are used throughout to indicate the same parts.

The device illustrated in Fig. i comprises a m manifold t supplied with a combustible mixture by a. compressor 2 which draws the mixture from a carburetter t. The quantity of the mixture adl mitted to the engine is regulated by the throttle valve 4 of the carburetter 3. A lever 8 is mounted on throttle valve l at the axis thereof.

The throttle valve t is controlled by theccmbined action ci a lever E actuated by the pilot and by the power member 6 of the relay device oi a boost control indicated in its ensemble generally by the reference numeral l. One ofthe ends it of a floating lever Il is connected by a rod ii to the throttle lever 8. The opposite end i2 of the oating lever 9 is connected by a rod i3, a' bell crank Il and a rody I5 vto the pilots control lever- 5. An intermediate point I6 of the floating lever t is fastened to the power member 6 oi' the relay device of the boost control 'L When the pilot moves the lever t, the movements of this lever are transmitted to the end t2 of the free lever 9 through the rod I5 the bell crank IB and the rod i3. The lever il then pivots round the fulcrum point IG of the lever 9 and. the displacements oi the end I2 of the lever 9 are thus transmitted toits other end I0. The movements of the end I0 are in their turn transmitted to the throttle valve Il through the intermediary'oi the rod IIJand ot the throttle lever t. Displacement of the pllots lever E inthe direction of the arrow I 'i corresponds to a closing of the valve t. Movements of the leveri in a direction to open the valve are limited by an abutment'it. In Fig. l the lever 5 has been illustrated in the position oi maximum opening of the valve, the lever li beingL in contact'withthe abutment tt.

When the power member 6 of the relay device of the boost control i moves, its movement is transmitted to the point I6 of the floating lever Q and -movi-rs the latter around the pivoting point G2 of'the leverand the rod I3, the position of which is determined by the position of the pilots lever 5.

.Movement oi the end il? of the lever t due to displacement or the power-,member t is transmitted to the throttle valve t through the 'interof the rod il and the lever t. A disfg5 placement downwards of `the power member 9 corresponds to a closing movement of the throttle valve The boost control 1, the details of which are illustrated in Fig. 2 comprises a chamber I9 which communicates by a conduit 29 with the intake manifold I on the delivery side of the compressor` 2 (Fig. l). The induction pressure is thus transmitted to the chamber I9. If the compressor 2 is cut out or ii. it is disposed on the intake side of the valve 4, the pipe 29 would have to open into the intake manifold I on the delivery side of the said valve 4.

The chamber I9 contains a manometric element constituted by a closed extensible element 2| fixed at the end 22' of the chamber I9 by a screwed spindle 23 carried by the end 25 of the element 2| and fixed by means of a lock nut 24. The spindle 23 permits the initial adjustment of the position o! .the element 2| in the chamber I9. At the end opposite to the spindle 23the element 2| carries a spindle 29 `passing through a guide 21.

The relay device of the boost control 1 comprises a cylinder 29 in which moves a power piston 29 loaded by a spring 39. The power member of the relay device is constituted by a rod 9 pivoted to the pin 3| carried by the base of the power piston 29. The cylinder 2'3 communicates by means of an orifice 32 with a cylindrical bore 33, in which slides a plunger 34 constituting a pilot member for the relay device. The cylindrical bore 33 communicates through a passage 39, with a pipe 3l which is connected in the circuit of the lubrieating oil pressure system of .the engine, and it communicates by a passage 31 with a pipe 39 for returning the oil.

The plunger 34 has two channels 39 and 4I) which communicate respectively with the passage 39 receiving oil under pressure and the discharge passage 31. that these passages are never covered. The part 4| oi' the plunger situated between the two channels 39 and 49 is capable oi' partly covering the orifice 32. In Fig. 2 the plunger has been illustrated in the neutral position. In this position, the orifice 32 projects on both sides of the part 4| oi' the plunger 34, so that the cylinder 29 communicates with the channel 39 and the oil Passage 33 under pressure on the one hand, and with the channel 49 and the discharge passage 31 on the other hand. The pressure which'exists in the cylinder 429 is intermediate between the oil pressure existing in the channel- 39 and the low pressure (discharge pressure) existing in the channel 43, and it depends on the relative section oi' the passages existing on either side oi' the part 4I o! the plunger 34. When the plunger 34 occupies the neutral position, the pressure in the cylinder 29 which acts on the upper face-of the piston 29 balances the force ofthe spring 39. If the plunger 34 moves to the right, the pressure in the cylinder 29 increases and becomes stronger than the spring 39. The oil under pressure coming from the passage 39 and penetrating the cylinder 29 through the channel 39 and the oriilce 32 then forces the pistons 29 and thereby lthe power element 9 of the relay device downwards. If. on the contrary, the plunger 34 moves to the lei't from the neutral position;v the pressure in the cylinder 2l decreases and the force of the spring 39 preponderates and pushes the piston 29 and the power element 9 up again driving the oil contained in the cylinder 23 -through the oriiice 32, the channel 49 and the discharge passage 31. A lever 43 pivots round a pin 44 carried by the 'I'he size of these channels is suchv body of the apparatus. One of the arms of the lever 43 carries a pin 49 on which is mounted a lever 49 which ends in a fork. The plunger 34 and the end 29 of the element 2| respectively carry studs 41, 49 which engage between the arms of the fork 49. The lever 43 and the fork 49 constitute a device for varying the datum oi the boost control. For a predetermined position oi' the lever 43 such as that indicated in Fig. 2, the pilot plunger 34 occupies the neutral position 'for a certain length l of the element 2|, that is to say, for a certain value of the induction pressure to which the element 2| is subjected. This particular value of the induction pressure is the rated induction pressure which corresponds to said predetermined position oi the lever 43. If the lever 43 moves through a certain angle around the pin 44, for example in clockwise direction, the element 2| must take up a length oi l' in order that the pilot plunger 34 may still occupy the neutral position. This length l' corresponds to a different value oi' the rated induction pressure and to each determined position oi the lever 43 corresponds a determined length of the element 2| and a determined value of the datum of the boost control.

The connection between the power member of the relay device and the device for varying the datum of the boost control consists oi' a pin 42 which connects the power member 9 to one of the arms of the lever 43. Owing to this connection, the datum of theboost control is a function of the position of the power member 9.

The operation of the device is as follows:

If it is assumed that the engine operates at a predetermined altitude, the lever 5 oi' the pilot being placed in a position of maximum aperturel" the various members occupy a position of equilibrium as long as the conditions ci' the running of the engin-e do not vary. This position is illustrated in Figs. 1 and 2; the pilot'plunger 34 occupies the neutral position, the induction pressure is equal to the rated induction pressure corresponding to the particular position occupied by the lever 43, and the element 2| has a length l.

If the pilot moves the lever 5 in the direction of the arrow I1, this movement is transmitted to the throttle valve 4, through the rod I9, the

bell crank I4, the rod I3, the lever 9 pivoting round the axle I9, the rod II and the throttle lever 9, and brings about a closure movement oi'{.ithe.thrott1e valve 4. The closure of the throttl'yalv'e 4 brin'g about a lowering of the induction pressure` and the-'element 2|, which is exposed to such'pressure, lengthens. I'he spindle 29 oi' the element'i'ZI moves towards the left and takes `with it the fork 4s which pivots around the pin 49. The fork 49 takes with it in its movement the stud 41 and the plunger 34 which is thus I displaced towards the left, from the neutral position. The relay device is put into action and` the spring 39 pushes the power piston 29 upwards. driving the oil contained in the cylinder 29 through the discharge passage 31. While moving upwards the piston 29 takes with it the power member 9, the movement ofI which is transmittedv to the throttle valve 4 through the lever 9 which pivots round the axle I2, through the rod I| and the valve lever 9, and the valve 4 opens again. In its upward movement, the power member 9 takes with it the lever 43 through the' intermediary oi' the pin 42, while the re-opening o! the valve 4 produces an'increase in the induction pressure which Vis expressed in the shortening of the element 2 I.

The movement of the lever 43 and the shortening of the element 2| have the effect of bringing back the pilot plunger 34 towards the right, that is to say, towards its neutral position. 'I'his 4neutral position is attained when the piston 29 has-traversed a-certain distance and when the` element 2| has a length l' greater thanv the initial length l. The corresponding induction pressure is equal to the `rated pressure which corresponds to the new position of the power member 6 and which is weaker than the initial rated pressure. This new rated pressure is obtained for a throttle opening-which is smaller than the initial opening. The plunger 34 then occupies the neutral position', the relay device is out of action, the power piston 29 is immobilised, and the system is again in equilibrium. It is thus seen that the moving of the lever 5 in the direction of the closing of the throttle valve has as a result a closure movement of the said valve, followed by a partial reopening; but the ilnal A position at which the throttle valve 4 is stabilised corresponds to a smaller opening than the initial opening ,so that the moving, of the lever 5 has inally had, as a result, an eiiective closing of the valve t.

If the pilot displaces the lever 5 more and more in: a direction to close valve 4, the power member 6 of the relaydevice is moved upwards more and more and the valve 4 is closed more and more, while the induction pressure diminishes. For a definite position of thelever 5,the

button 49 carried by the piston 29 abuts against the upper end of the cylinder 28. If the pilot moves the lever 5 in the direction of closure of the valve 4 beyond this position, the power piston 29, which has reached theend of its stroke is no longer capable of intervening tobring about a partial re-opening of the throttle valve -although the induction pressure decreases` below the.'y rated pressure, so that the throttle valve is found to be controlled solely by the lever 5.

It must be noted that the valve 4 reaches'gits position of closure (slow-running position) for a position of the lever 5 which is always the same v whatever the altitude,.since the power piston 29 is always at the end of its course, that is to say, it occupies an invariable position, when the slowrunning position has been reached.

When the engine is operating at ground level the lever 5 being placed in vits position of maximum opening, that is to say, in contact with the abutment i8, the power piston 29 and the power member Soccupy a' deilnite position; the throttle valve 4 being partially closed, and the motor develops the maximum power allowed. -If the engine rises to a height, thelever 5 being always maintained in the position of maximum opening, the power piston 29 rises in the cylinder 28 taking with it the power member 6. In the course oi this displacement it opens the throttle valve more and more while vit diminishesprogres# sively the datum/oi' the boost control. The induction pressure which remains constantly equal to the rated induction pressure at each instant, itself diminishes. When the' height reaches the rated height, the power piston 29 abuts against the upper end of the cylinder 28vand the throttle valve li then attains complete opening. It has been pointed out that this decrease in the maximum induction pressure, when the altitude increases, is one advantage of the invention, becausev it is desirable thatthe engine should de; velop at ground level a power slightly superior to the power which it is capable of developing at a height. z

The difference between* the maximum induction pressure on lthe ground and the maximum induction pressureV at the rated height depends on the determination roi the device for varying the datum ofthe boost control, and depends in particular on the ratio of the lengths of the arms of the lever 43 and, the respective distances between the studs 41 and 48 and the pin 4l. For example, these various lengths will be determined in sucha a way that the maximum induction-pressure allowed (rated induction pressure for the maximum opening-position of the lever 5) should be equal to 1,000 gr./cmi2 on the ground and 900 gr./cm.2 at the rated heights In these conditions, the diii'erence between the maximum power which the engine is capable of developing on the ground and at the rated height for a definite regime will be of the order of 10%. A modification of these variousvlengths willfmake it possible to alter this difference in power as desired.

The boost control illustrated in Fig. 3 diiers from the boost control illustrated in Fig, 2 in the form 'of construction of the device varying the datum of the boost control. In the device illustrated in Fig. 3 the central portion 50 of the pilot plunger 34 is formed helicoidal. The plunger 34 is capable of being turned in the cylindrical bore 33, and it is kept pressed against the face 5| of the element 2| by a spring 52.

54 which engages in a seat of the same form 55 35 in the pilot plunger 3d. 'I'he shaft 53 therefore carried with it in its rotary movement the pilot" plunger 34, while allowing the plunger to move freely in a longitudinal direction. f The rotation of the shaft 53 is obtained by means of a lever 56 mounted on the end of the shaft and connected by a rod 5l to the end 53 of the lever 43. The lever 4,3 pivots round the pin 44 carried by the body of the apparatus, and its opposite endg is connected by apin 42 to the power member -5 of the/,relay device. The combination of lever 43, rod'f', lever 5S and shaft 53 provided with an end 5S, constitutes the device for varyingA the datum of the boost control. If the power member 64 moves upwards, it brings about a rotation of the pilot-plunger 34 through the intermediary of the lever 43;'the rod 5l andthe shaft 53 having the squared end 54. Owing tothe helicoidal form of the central portion.- 50 of the plunger 34, the central portion is no longer opposite the oriiic'e 32, that is to say, lthe plunger is nov longer in the inoperative position. 'Io bring back the plunger to the inoperative position it is necessary that the element Ament 2l. The opposite end 25 of the veleme'ntf`2i should lengthen by -a denite amount.

The'

movement of/the power element 6 in the direci tion of the opening of the valve thus increases In the device niustrated in rig. 4 tnepiiot plungerv 3d is carried bythe end El of the elevplunger 34, while the power meniberd could control its longitudinal movements. l

carries a spindle ill passing through a bearing Il. A lever l2 pivoted at 63 is connected by a rod I4 to one ot the arms of the lever 43, which latter is itself connected by the pin 42 to the power member 5 of the relay device. The lever 52 is provided with a slot 85 in which is engaged a pin 3l carried by the spindle 80 of the element 2|. The combination of the lever 43, the rod 54, the lever 52 and the spindle 60 constitutes the device for varying the datum of the boost control.

' The pilot plunger 34 being integral with one of the ends 5| ot the element 2|, the position of the end 5| which corresponds to the inoperative position ot the pilot plunger 34 is invariable and independent oi' the position of the power member I. When the Ipower member 8 is moved upwards it takes with it the device for varying the datum of the boost control and moves the element 2| to .the right through the intermediary o! the lever 43, the rod 64, the lever 62 and the spindle 53. In order that the pilot plunger 34 may again ccupy the inoperative position after such a movement, it is necessary that the element 2| should lengthen by a certain or deiinite amount, in order that its end 5| should take up the invariable position again which corresponds to the inoperative position of the pilot plunger 34. It can be seen that, in the arrangement illustrated in Fig. 4 as in the arrangement Villustrated in the Figs. 2 and 3, a movement of the power member 5 o! the relay device in the direction oi' opening the throttle valve increases the length of the manometric element which corresponds to the inoperative position of the pilot member, and the operation of the device illustrated in Fig. 4 is completely analogous to the operation of the devices illustrated by Figs. 2 and 3.

In the device illustrated in Fig. 5 the end 25 of the element 2| is nxed in the end 23 of the chamber I3 in the same way as the device illustrated in Fig. 2. A lever 51 pivotal about a pin 53 has one end B3 thereof loaded by a spring 10 which is disposed in a housing 1| made in the body of the apparatus. A hollow piston 12 sliding in the cylindrical housing 1| is interposed between the spring 1l and the end 63 of the lever l1. The opposite end 13 of the lever 31 bears against one end oi' the pilot plunger 34 by the force of the spring 10. The i'orce of this spring, moreover, maintains the opposite end of the pilot plunger 34, in contact with the face 5| oi' the element 2|. 'I'he spring 10 is compressed between a the hollow piston 12 and the head 14 of the spindie 15 sliding ln a guide channel 15. 11 of the spindle 15, is maintained in contact, by means of the spring 15, with a roller 18 carried by the lever 43. 'I'he lever 43 pivots about a pin 44 carried by the body ot the apparatus and is connected to the power member 5 of the relay device by a pin 42. The combination of the lever 43 and the spindle 15 constitutes the device for varying the, datum of the boost control.

The force of the'spring is transmitted to the end 5I of the element `2| through the intermediary of the hollow piston 12, the lever l1 and the pilot plunger 34. For a determined value of the induction pressure transmitted to the chamber |3the element 2| assumes such a length that its own elastic resistance, possibly increased by any elastic means disposed inside this element,

The end u balances th induction pressure to which the element is subjected, externally assisted by the force of the spring 10.

When the pilot plunger 34 occupies the inoperative position, the position of the end 5I oi the element 2| is invariable and, as the opposite end 25 of the element 2| is xed, the length of the element which corresponds to the inoperative position of the pilot plunger 34 is invariable. If the power member 8 moves upwards, it takes with it the lever 43 and compresses the spring through the intermediary of the roller 13 and the spindle 15. The force which the spring exerts on the element through the intermediary of the hollow piston 12`l the lever 81 and the pilot plunger 34, increases, which brings about a shortening oi' the element. In order that the element may recover its initial length and the pilot plunger be brought baci'. to its inoperative position, the induction pressure must be lowered to such an extent that the decrease in this pressure;'which acts on the element, balances the increase in the thrust of the spring. It can thus be seen that a movement of the power member in a direction to open the throttle valve brings about a decrease in the rated induction pressure.

The operation of the device illustrated in Fig. 5 is analogous to the operation of the devices illustrated in the preceding figures. The control lever 5 of the pilot being placed in a position of maximum throttle opening, the power piston 29 and the power member 6 occupy a basic position ii' the conditions oi' the running of the motor are stable and if the altitude does not vary. The pilot plunger 34 occupies the vinoperative position. I! the pilot moves the lever 5 in a direction to close the throttle valve, the movement brings about first oi' all a partial closure of the said valve. The induction pressure decreases and, consequently, the element 2| lengthens, displacing the pilot plunger 34 from its inoperative position. The relay device is put into action, and the piston 29 of the power member 8 is displaced upwards. The lever 43 is actuated and movement is transmitted to the spindle by the roller 18. This movement of the spindle 15 has the eiect o1 increasing the compression of the spring 10. The movement of the power member 6 brings about a partial re-opening of the throttle valve 4. 'I'he partial re-opening as well as the increase in the compression of the spring 10, both have the eiect of reducing the length of the element 2| The element 2| again takes up its initial length, for which the pilot plunger 34 occupies the inoperative position, for a value of induction pressure smaller than the initial value, since the compression of the spring 10 is greater than the initial compression. This new value o! the induction pressure is attained by an opening of the throttle valve 4` which is smaller than the lnitial`opening, so that moving the lever 5 in a direction to close actually has for a result the closing oi the throttle valve 4.

In the device illustrated in Fig. 6, as in the device illustrated in Fig. 5, the device for varying the datum of the boost control actuated by the power member of the relay device works by means of a modliication of the intensity of a force loading the manometric element, but instead of regulating the force' of a spring, the device regulates the pressure of a iluid.

In the device illustrated-in Fig. 6 the element 2| is connected. to the pilot plunger 34 by a lever 13. The cylindrical bore 33, in which the pilot plunger 34 slides, communicates with a chamber 80 containing oil, and the end 8| ofthe plunger 2,233,319 -34 is subjectedl to the oil pressure in the chamber 8|. 'I'he chamber 88 communicates on-the one hand withvthe discharge passage 31 through a calibrated orifice 82, and on the other hand with the cylinder 28 by a longitudinal slot 83. The longitudinal slot 83 is partially covered by the piston 28, and the length of the slot 83 un covered varies as a function of the position of the power piston 29, which thus regulates the section of the passage between the cylinder 28 and the chamber 88. As long as the piston 29 haswnot reached .one of 'the ends of its course, the pressure of the oil in the cylinder 28 .is well determined, since it balances the force of the spring 38. The pressure in the discharge passage 31 is practically equal to atmospheric pres` sure. 'I'he pressure in the chamber 88 is intermediary between the pressure existing in the cylinder 28 and the pressure existing in the discharge passage 31, and the value of the pressure in the chamber 88 depends on the ratio between the section of the xed calibrated orifice 82 and the section of the uncovered part of the slot 83.

The pressure in the chamber 88 diminishes as the uncovered section of the slot 83 diminishes, that is to say, as the power piston 29 moves upwards (direction to open the throttle valve) The combination of chamber 88, calibrated orifice 82 and slot 83 the uncovered portio'n of which is controlled by the piston 28, constitutes the device for varying the datum of the boost control.

The variations in pressure which the oil contained in the chamber 88 exerts on the end 8| of the pilot plunger 34, when the power piston 29 is. displaced, plays the same role as the variations in the force of the spring 18 (Fig. 5) so that the operation ofthe d evice illustrated in Fig. 6 is analagous to the operation of the device illustrated in Fig. 5. It will be noticed, however, that owing to the presence of the lever 19 in the device illustrated in Fig. 6 the movement of the pilot plunger 34 to the rightn this device correspends to .the movement of the plunger towards the left in the device illustrated in Fig. 5 and inversely/It is obvious that the plunger 34 must be given a suitable section in order that the thrust exerted by the oil in the chamber 88 on the end 8| of the plunger 34 has a suitable value. Further, the slot 83 could bereplaced by a series of orifices provided in the wall separating the cylinder 28 and the chamber 88 and disposed at different levels.

Th/e device illustratediin Figs. 'I yand 8 can only be applied to engines provided with a compressor disposed on the discharge sideof the throttle valve. In this device the chamber I9 containing the element 2| communicates on the one hand withthe intake manifold i on the discharge side of the compressor 2 by a passage 28 in which is disposed a calibrated oriiice 84,' and on the other hand with a portion 85 of the intake manifold 'situated between the valve 4 and the compresson 2 by a conduit 88. In this conduit 88' is disposed a calibrated orifice 81 the section of which is regulated by a. profiled spindle 88 which is an extension of a shaft 89 which passes through a guide 98, and it is attached to the powermember 8 of the relay device by the lever 43 pivoting about a pin 44. The power member 8 thus controls the profiled spindle 88 which controls the passage section of the orifice 81. The profile of the spindle 88 is such that this passage section diminishes as the power member, 8 moves Aupwards, that isto say, in the direction to opening ofthe throttle valve 4.

,its

Whereas, in all the forms of construction which have been described above, the pressure in the chamber I3 is equal to the induction pressure, the pressure in the chamber I8 in the device illustrated in the Figs. '1 and 8, is intermediate be,- tweenthe induction pressure (pressure posterior to v.the compressor) and the pressure at the entrance to the compressor.

The operation of the device is as follows.

The 'control lever I of the pilot being placed in the position of maximum throttle opening, the power piston 29 and the powermember 8 occupy a basic position if the conditions of running of theengine are stable and if the altitusdev does not vary. The pilot plunger 34 occupies the in'- operative position, and the passage section of the oriiice 81 is determined by the particular position occupied by the power member 8. The induction pressure is equal to the rated induction pressure which corresponds to the particular position of the power member 8. The pressure in the chamber i9 is intermediate between the pressure existing anterior to the compressor 2 at 85 and the rated induction pressure. and its value is determined by the position of the profiled spindle 88. Y

If the pilot moves the lever 8 in a direction to close, the movement brings about iirst of all a partial closure of the valve 4. There results alowering of the pressures which exist, above and below the compressor 2 and, consequently, a lowering ,of the pressure existing in the chamber I9. The element 2| lengthens and dispiaces the pilot plunger 34 towards the left from its inoperative position. The power piston 29 andthe power member 8 move upwards, under the influence of the thrust of the spring 38, driving out theoil contained in the cylinder 28. In this movement,

the power member 8 takes with it the throttle valve 4 in a direction to open. At the saine time it takes with it the profiled spindle 88 through the intermediary of the lever 43, and the passage section of the orifice 81 diminishes.

. The opening movement of the throttle valve 4 and the decrease in the passage section oi the orifice 81 both have the effect of increasing the pressure existing in the chamber I9. The element 2| shortens and brings back the pilot plunger towards the inoperative position. The inoperative position is attained when the pressure in the chamber i8 has the value which it had initially, but, as the oriiice81 has then a smaller passage section than the initial passage section, this position is attained for an opening of the throttle valve 4 smaller than the initial opening and for a value of the rated induction pressure smaller than the initial rated induction pressure. The movement of the lever 5 in the direction of the closure of the throttle valve will thereiorehave had as a final result an actual closure of the valve 4.

It is clear that the profiled spindle 88 could is regulated by the throttle valve 41| of the car- 1.

burettor 3 `andby a second throttle valve 42.

The throttle valve 41 is controlled by the pilots lever through the intermediary of the rod |51 and the lever 81. In the` figure the throttle' valve 41 has been illustrated in its wide open position, the lever 5 being in contact with the stop I8. 'I'he throttle valve 42 is controlledV by the powei` member of the relay device of the boost control 1 through the intermediary of the lever 82. The detail of the boost control 1 is illustrated in Fig. 2. The boost control 1 comprises a chamber i9 which communicates by a conduit with the admission intake manifold at the discharge side of the compressor 2 (Fig. 9). The induction pressure is then transmitted to the chamber I9. If the compressor 2 is cut out or if it has been disposed between the throttle valves 41 and 41, or posterior to the throttle valve 41, the pipe 20 should open into the intake manifold posterior to the valve 41. 'I'he throttle valve 4z itself can besides be placed anterior lto the throttle valve 41, instead of being placed posterior to said throttle valve, as has been illustrated in Figure 9.

'I'he operation of the device is as follows: Assuming theengine functions at a definite height, the pilots lever 5 being in contact with the abutment I8 and the throttle valve 41 being wide open, the various members of the boost control and the throttle valve 42 occupy a posi- -tion of equilibrium as long as the conditions of running the` motor do not vary; the throttle valve 41 is partially closed as long as the altitude is less than the rated altitude. This position is illustrated in Figs. 9 and 2. The pilot plunger 34 occupies the inoperative position, the induction pressure is equal to the rated induction pressure corresponding to the particular position occupied by the lever 4I, and the element 2| has a length l.

If the Vpilot moves the lever 5 in the direction of the arrow I1, in such a way as partially to close the throttle-valve 41, this partial closure produces a lowering of the induction pressure existing in the intake manifold and the relay device is put into action as previously described. This movement of the relay device is transmitted to the throttle valve 42 by the lever 81, and this throttle valve, which was partially closed, re-

vopens and brings about an increase in the induction pressure. 'I'he corresponding induction pressure is equal to the'rated pressure which corresponds to the new` position of the power member-,s and is 1ess than the initial rated bressure. When this new rated pressure is obtained the throttle valve 4z is wider open than initially, whereas the'throttle valve 41 is more closed than initially. The plunger I4 then occupies the inoperative position, the relay device is out of action, the power the system is again in equilibrium.

'I'he induction pressure in the manifold I is equal to the new value of the rated pressure and in consequencaless than the initial induction pressure. 'I'he quantity o f air or mixture admitted to the engine is itself less than the initial quantity o f air or mixture. It can thus be seen that 4the movement of the lever 5 in the direction of closing of the throttle valve 41 has as a result a lessening of the quantity of air or mixture admitted to the engine. 'I'he arrangement described in Fig. 9, in which the lever 5 and the boost control 1 control two different throttle valves, therefore obtain progressiveness of the i regulation of the quantity of air or mixture during the movement' of the pilots lever 5 in the closing direction and in the same manner as the device described with reference to Fig. 1.

When the engine functions at ground level the piston 28 comes torest, and

lever 5 is placed in the position of maximum throttle opening, that is to say, in contact with the abutment i8, the power piston 28 and the power member 6 occupy a predetermined position, the throttle valve 42 being partially closed and the engine develops the maximum power allowed. Ii the engine is brought to an altitude, the lever 5 being maintained in the position of maximum opening, the power piston 2l rises in the cylinder 28 and takes with it the power member 6. In the course of this displacement, it opens the throttle valve 42 more and more, while it diminishes the datum of the boost control progreively.

The induction pressure which remains constantly equal to the rated induction pressure at each instant, diminishes itself. When'the altitude reaches the rated altitude, the power piston abuts against the upper end of the cylinder 28 and the throttle valve 42 then reaches its total opening. 'Ihe device illustrated in Fig. 9 therefore brings about a decrease in the induction pressure and, consequently in the maximum quantity of air or mixture admitted to the engine when the height increases, in the same manner as the device illustrated in Fig. 1.

In the device illustrated in Fig. 10, the compressor 2 is operated by a shaft |55 through the intermediary of a variable gear coupling, indicated generally by the reference numeral 56.

` The shaft |55 is either the shaft of the engine or a shaft driven thereby. The variable coupling |56 comprises two discs, having annular depressions |51 and |58. ,The disc |51 is driven by the driving shaft |55, while the disc |58 drives the shaft |59 of the compressor. of the disc |58 by the disc |51 takes place through the intermediary of one or several rollers |60. 'I'he spindle 6| of the roller |60 pivots in bearings |62 carried by the frame |63 (Fig. 1l). The frame |68 carries at its ends pins |64 turning in fixed bearings |65. The movement of the `frame |63 is effected by means of ,a lever |65 whereby it is possible to modify the position of the roller |60 in relation to the discs |51|5l and thus alter the ratio of the diameters of the circles of contact |61 and |68 between the roller |60 and the discs |51 and |58. The arrangement therefore modifies the ratio of the step up of the coupling |56. l

The coupling which is known in itself, has been illustrated in a. schematic manner only, and in particular the arrangements which assure the friction between the roller |60 and the discs |51 and |58, in order to avoid an excessive slip between the various members have not been indicated.

The lever |66 is controlled by the power member 6 of the relay device 0f the boost control by the intermediary of a bell crank |69 and the rod |10. When several rollers |60 are spread'around the circumference of the coupling they are simultaneously controlled by the power member 6. When the power member 6 is displaced upwards the lever |66 and the roller |B07turn in the direction of the arrow |1l, and the step up of the coupling increases. The speed of the compressor therefore increases (for a given speed of the engine), and this increase in the speed produces an increase in the quantity of air or mixture admitted to the engine and an increase in the delivery pressure of the compressor, that is t0 say of the induction pressure existing in the intake manifold Finally, the control of the speed of the compressor by the power member 6 of the re- The driving,

lay device of the boost control has exactly the same effect as the control of the throttle valve 42 by the power member in the arrangement illustrated in Fig. 9.

Thus it is to be understood that the functioning of the device illustrated in Fig. 10 is absolutely analogous to the device illustrated in Fig. 9. In the one and in the other case the movement of the pilots' lever 5 in a direction to close the throttle valve bnings about an actual and progressive decrease, without lost motion, of the quantity of air or mixture admitted to the engine, and the maximum induction pressure which corresponds to the full open position of the lever diminishes when the altitude increases. The

functioning would be the same if the arrange-.

ment controlled by the power member 6 of the relay device of the boost control comprises any other device for regulating the quantity of air or mixture admitted to the engine.

In the device illustrated'in Fig. 12 the throttle valve 41 controlled 'by the pilots lever 5 is disposed on the delivery side of the compressor 2. The throttle valve 42 controlled by the power member 6 of the boost control 1 is disposed at the entry side of the compressor. The valve 42 could, however, be disposed at the delivery side of the compressor anterior to the throttle valve 41. The compressor 2 could be Acut out if desired. The conduit 20, which connects the chamber I9 of the boost control to the intake manifold I, opens into the latter at the point |14 between the compressor 2 and the throttle Valve 41. If the throttle valve 42 was disposed at the exit of the compressor 2, or if the compressor is cut out, the pipe 20 would open into the intake manifold between -the two throttle valves 42 and 41.

In such an arrangement, the regulation, by the pilots lever 5, of the quantity of air or mixture admitted to the engine isalways progressive and without lost'l motion, even if the boost control is not a boost control with a variable datum. In such a case in fact the control of the throttle valve 41 by the boost control has for effect the maintenance of a constant pressure in the region |14 of the manifold I. Any modification of the opening of the throttle valve 41 by the lever 5 of the pilot will obviously produce a variation in the induction pressure on the delivery side of this valve. The maximum induction pressure which corresponds to the widest opening of the valve 41 would, therefore, be invariable and equal to the constant pressure maintained by the functioning of the boost control in the region |14 of the manifold The boost control which is the subject of the invention, applied to such an arrangement, makes it possible to/vary the maximum induction pressure as a function of the altitude. The lever 5 being maintained in contact with the abutment I8 and the throttle valve 41 being wide open, an increase in the altitude brings about first of all a lowering of the pressure in the intake manifold and, in particular, in the region |14 of this manfold. This lowering of the pressure puts into action the relay device of the boost control; the power member 6 moves upwards and increases the opening of the throttle valve 42.

This increase in the opening produces an increase in the pressure in the region |14 of the manifold and the valve 42 stabilises itself when the rated induction pressure is re-established in the region |14; this equilibrium pressure is obtained for a position of the power member 6 different to the initial position thereof, and in consequence. the induction pressure in the region |14 has a different value from its'initial value, since, owing to the connection between the power member 6 and the device for varying the datum of the boost control, the movement of the power member 6 brings about a variation in the rated induction pressure. In the device illustrated in Fig. 12, the maximum induction pressure is therefore easily variable as a. function of the altitude. c v

In the arrangement illustrated in Fig. 12, it is clear that the power member 6 of the relay device could control a device for the variation of the speed of -the compressor 2, such as that which has been illustrated in Fig. 10, instead of controlling a throttle valve. This power member could similarly control any other device for regulating the quantity of air or mixture admitted to the engine.

If the connection lbetween the power member 6 and the device for varying the datum of the boost control is carried out as has been illustrated in Fig. 2, the maximum induction pressure decreases as the altitude increases. But as has been pointed out in certain engines this connection may be altered in such a way that the maximum induction pressure increases as the altitude increases, or even in such a way that it varies according to a predetermined law increasing at certain altitudes and decreasing at other altitudes. It must be noted `that in reality, the maximum induction pressure doesI not vary directly as a function of' the altitude, that is to say the atmospheric pressure, but it varies dlrectly as a function of the pressure in the region |14 of the manifold, a pressure which is in itself a function of the altitude and the speed of the engine.

In Fig. 13 a further modification of the boost control illustrated in Fig. 2 has been illustrated, in which a movement of the power member 6 upwards brings about an increase in the rated induction pressure, instead of bringing about a decrease of the latter, as in the device illustrated in Fig. 2. This result is obtained -by a simple modification of the form of the lever 43 and the fork 46, the lever and fork 'being replaced respectively by a lever 431 and a fork 461. It can be seen clearly, according to Fig. 13 that a movement of the fork 461 which corresponds to a determined movement of the lever 431, is in the opposite direction to -the movement of the fork 46 (Fig. 2), which corresponds to the same movement of the lever '43. If the boost control illustrated in Fig. 13 is substituted for the boost control illustrated in Fig. 2 in the device illustrated in Fig. 12, the maximum induction pressure lncreases, instead of decreasing, when the `altitude increases.

In Fig. 14 a variant of the boost control illus-v trated in Fig. 2 has been illustrated, which allows the datum of the boost control to vary as a function of the position of the power member 6 of the relay device of the boost control according to an arbitrary law. In this device, the fork 462 is pivoted about a pin 41 carried by the plunger 34. The stud 48 carried by the spindle 26 of the element 2| engages in the end of this fork. A lever 432 pivoted upon a pin 44 and replacing the lever 43 of the device illustrated in Fig. 2 is connected to the power member 6 by the pin 42. The lever 432 carries a stud |80 which engages in a slot |8| carried by the end of the fork 462. By giving a suitable form to the slot |6| a definite variation of the datum oi the boost control as a function of `the displacement of the power member 6 can be obtained.

Of course, in the devices illustrated in Figs. 9, 10 and 12, the boost control shown in Fig. 2 maybe replaced by any other Iboost control previously described.

It will easily `be seen, in the various boost controls illustrated, how it should be possible to invert the direction of the variation of the datum of the boost control as a function of the displacements of the power member of the relay device. In the devices illustrated in Figs. 3, 4, or 8, the lever 43 could -be given an analogous modification to that which has been illustrated in Fig. 13. In the device illustrated in Fig. 3, the helicoidal collar 5U, the step of whici is to the right, could also be replaced by a he icoidal collar with a step to the left. In the device illustrated in Fig. 8, it is also possible to modify the profile of the needle 88, this needle growing narrower towards the top, instead of growing wider. In the device illustrated in Fig. 6 for example, the pressure existing in the chamber 80 is caused to act on the right end of the plunger 34, instead of making it act-on the left end as has been illustrated.

In order to alter the direction of the variationof the maximum induction pressure as a function of the altitude, it is likewise possible, in a general manner to invert the direction of the movement of the power member of the relay device and at the same time to invert the direction of the movement of the member regulating the quantity of air or of mixture admitted to the engine controlled by the said power mem'ber, without modifying the connection between the power member of the arrangement for varying 4the datum of the boost control. In the device illustrated in Figs. 9 and 2, for example, the pipe for the oil under pressure 35 and the oil discharge pipe 38 would be interchanged. In this way, a lowering of the pressure in the ychamber |'9 would bring about a movement downwards of the piston 29, instead oi a movement upwards. At the same time the direction of opening of the throttle valve 42 controlled by the power member B will be inverted -by turning this valve 42 through 90 degrees for example compared with the control lever 82. The connection between the power member 6 and the fork 46 by the lever 43 remaining unaltered, a movement upwards of the piston 29 will also bring about a decrease in the rate'd induction pressure, lbut this movement then corresponds to a closure of the throttle valve 42, that is to say a diminution of the quantity of air or mixture admitted to the engine, instead of corresponding to an increase in the latter, as in the device illustrated in Figs. 9 and 2. An analogous modication in all the other forms of construction of the vboost control or of its applications illustrated will lead to the same result.

It must also be pointed out with reference to the direction of the variation of the datum of the boost control as a function of the displacements of the power member of the relay device, that the yboost controls with relay devices often have a tendency to throb, that is to say to keep up a periodic oscillation round a point of equilibrium. This throbbing or oscillation is obviously harmful, since it prevents even running of the engine. By connecting the power member of the relay vdevice to the device for varying the datum of the boost control in such a way that a movement of the said power member in a direction to increase the quantity of air or mixture admitted to the engine will bring about a decrease in the rated induction pressure, will improve the functioning of the boost control in the sense that it reduces the possibilities of pulsation or throbbing of the latter. The devices which form the subject of the invention could be used, in certain cases, for the sole object of suppressing or reducing the harmful throbbings of the boost control.

On the contrary, if the connection between the power member and the device for varying the datum of the boost control is carried out in such a way that a movement of the said power member in a direction to increase the quantity of air or mixture admitted to the engine will bring about an increase in the rated induction pressure, this connection is favourable to throbbing and tends to increase the effect. Harmful throbbings will therefore 'be avoided by decreasing the speed of displacement of the power member' when the relay device is in action. In the arrangement illustrated in Fig. 2 for example the section of the orice 32 will be reduced. Under these conditions, `the throbbings could be suppressed, but the relay device will take longer to reach a position of equilibrium.

As has been pointed out, it is necessary, in the greater number of cases, to diminish the maximum induction pressure when the altitude increases, which renders it necessary to use the rst method of connection, that is to say the method of connection which favours the suppression of the throbbing and obtains the benefit of the two possi-ble advantages of the invention, namely the variation of lthe maximum induction pressure as a function of the altitude and the suppression of the throbbing of the boost control.

In the devices illustrated in the annexed drawings, the pilots lever controls a throttle valve disposed in the intake manifold, but it is clear that this lever, as also the power member of the boost control, could control any other device for regulating the quantity of air or mixture admitted to the engine, as for example, a compressor having a variable speed.

In the present application, the carburetor has been illustrated in a very schematic manner and the fuel feed has not `been illustrated. The fuel feed and the point in the manifold where introduction of the fuel takes place matters little as regards the present invention. In the arrangement illustrated in Fig. 9 for example the fuel can be introduced on the intake side of the valve 41, between the valves 41 and 42, on the discharge side of the valve 42 or on the discharge side of the compressor 2, or it can even be injected directly into the cylinders of the engine. The presence of fuel in the air sucked in, does not in fact eilect the functioning of the devices described, and the fact that the fluid the delivery of which is regulated is pure air or a mixture of fuel is immaterial.

Inall the devices which have been described by way of example, it has been assumed that the uid force used in the relay device is the lubrieating oilwhich is under the pressure. This fluid force could be the compressed mixture (or compressed air) issuing from the compressor associated with the engine, without necessitating modications in the apparatus except, however, in the dimensions of the various members. The supply pipe 35 of the oil under pressure will then be attached to the discharge of the compressor,

while the discharge pipe 38 will be attached to the inlet of the compressor.

In all the devices described, with the exception of the device illustrated in Fig. 3, in which the relay device necessarily employs iiuid under pressure, the type of relay device described could be replaced by any relay device, conditional on replacing respectively thepilot plunger. and the power member 6 illustrated by pilot members and power members ofthe relay device of any kind.

Finally it must be noted that the essential of the invention resides in a disposition which is internal to the. boost control unit, namely an operative conection between the power member, the relay device and the means for varying the datum of the boost control. The mechanical arrangement by which the movements of the power member of the relay device superimpose themselves upon the movements of the control lever of the pilot to produce the resultant movement of the lthrottle valve does therefore not affect the carrying into effect of the invention. The arV rangements which, in the examples described bring about this combined control could be replaced by any other equivalent device. For example it would be possible, in order to( realise this combined control, to utilise the arrangement of pivoted levers described in the specification of British Patent .No. 291,152 or the dierential gearing device described in the specification of British Patent No. 356,619.

What we claim and desire to secure by Letters Patent is:

1. A variable datum boost contrclnwith a relay device having a pilot member and-a power member, for an internal combustion-engine having an induction manifold and a control device therein, operatively connected with the boost control power member, for controlling the amount of air or mixture supplied to the engine, which comprises, in combination, a chamber, a passage for `connecting said chamber.v with said induction manifold posterior to said kcontrol device, a mano- .metrio element in said-chamber, an operative Jso connection between said manometric element and said pilot member, means for imparting a load on said manometric element, and means responsive to said power member for varying the load on said manometric element.

- 2. A variable datum boost control with a relay device having a Ipilot member and a power member, for ,an internal combustion engine having an induction manifold and a control device therein, operatively connected with the yboost control power member, for controlling the amount of air or mixture supplied to the engine, which comprises, in combination, a chamber, a passage for connecting said chamber withsaid induction manifold posterior to said control device, a manometric element in said chamber, an operative connection between said manometric element and said pilot member, a spring for loading said manometric element, and means operative by said power member for varying the pressure exerted by said spring on said manometric element.

3. In connection with an internal combustion engine having an induction manifold 'and a throttle valve therein, a throttle control, which comprises, in combination, a pilots lever, an operative connection between said pilots lever and said throttle valve, a chamber, a passage for connecting said chamber with said induction manifold posterior to said throttle valve, a manometric element in said chamber, a relay device having a pilot member and a power member, an

operative connection between said manometric element and said pilot member, means for imparting a load on said manometric element, means responsive to said power member for varying the load on said monometric element, and

means operative by said power member for altering the connection between said pilots lever and said throttle valve.

4. In connection with an internal combustion engine having an induction manifold and a throttle valve therein, a throttle control, which comprises, in combination, a pilots lever, an operative connection between said pilots lever and said throttle valve, a chamber, a passage for connecting said chamber with said induction manifold posterior to said throttle valve, a manometric element in said chamber, a relay device having a A'pilot member and a power member, an operative connection between said manometric element and said pilot member, a spring for loading said manometric element, means operative nby said -power member for varying the pressure exerted by said spring on said manometric element,l and means operative by said power member for altering the connection between said pilots lever and said throttle valve.

5. In connection with an internal combustion engine having an. induction manifold and a throttle valve therein, a throttle control which comprlses,`in combination, a 'pilots lever, an operative connection between said'pilots lever and said throttle valve, a variable datum boost control responsive to the pressure in said manifold posterior to said throttle valve, a relay device in and said throttle valve, a variable datum boost control, a chamber in said boost control, a passage for connecting said chamber with said mani` fold posterior` to said throttle valve, a manometric element in said chamber, a relay device having a pilot member and a power member, an operative connection between said manometric element and said pilot member, means operative by said power member for altering the connection between said pilots lever and said throttle valve, and means operative by said power member for lowering the rated induction pressure as said power member moves in the direction of' opening said throttle valve.

1. In connection with an internal combustion engine having an induction. manifold and a throttle valve therein, a throttle control which comprises,l inl combination, Aa pilots lever, an operative connection between said pilots lever and said throttle valve, a variable datum boost control, a chamber in said boost control, a passage for connecting said chamber with l said manifold posterior to said throttle valve, a manometric element in -said chamber, a relay device having a pilot member and a power member, an operative ,connection between saidnianometric element ,and said pilot member, means operativeby said power member for altering the connection between said pilots lever and said throttle valve, and means operative by said power member for increasing thelength of said manometric element which corresponds to the inoperative position of said pilot member, as said power member moves in the direction of opening said throttle valve.

8. In connection with an internal combustion engine having an induction manifold and a throttle valve therein, a throttle control which comprises, in combination, a pilots lever, an operative connection between said pilots lever and said throttle valve, a variable datum boost control, a chamber in said boost control, a passage for connecting said chamber with said manifold posterior to said throttle valve, a manometric element in said chamber, a relay device having a pilot member and a power member, means operative by said power member for altering the connection between said pilots lever and said throttle valve, a 'floating lever, and operative connections from three different points of said floating lever respectively to said manometric element, said pilot member, and said power member, said last mentioned operative connections being so designed that the length of said manometric element which corresponds to the inoperative position of said pilot mem-ber increases as said power member moves in the direction of opening said throttle valve.

9. In connection with an internal combustion engine having an induction manifold and a throttle valve therein, a throttle control which comprises, in combination, a pilots lever, an operativeconnection between said pilots lever and said throttle valve, a variable datum boost control, a chamber in said boost control, a passage for connecting said -chamber with said manifold posterior to said throttle valve, a manometric element in said chamber, a relay device having a pilot member and a power member, an operative connection between said manometric element and said pilot member, means operative f by said power member for altering the connection between said pilots lever and said throttle valve, means for imparting a load on said manometric elementl and means rative by said power member for increasing the load on said manometric element as said power member moves in the direction of opening said throttle valve.

10. In connection with an internal combustion engine having an induction manifold and a throttle valve therein, a throttle control which comprises, in combination, a pilots lever, an operasaid pilots ,lever and tive connection between said throttle valve, a variable datum boost con:

trol, a chamber in said boost control, a passage for connecting said chamber with said manifold posterior to said throttle valve, a manometric element in said chamber, a'relay device having a pilot member and a power member, an operative connection between said manometric element and said pilot member, means operative by said power member for altering the connection between said pilots lever and said throttle valve, a spring for loading said manometric element, and means operative by said power member for in.- creasing the strength of said spring as said power member moves in the direction of opening said throttle valve.

11. In connection with an internal combustion engine having 'an induction manifold, a supercharger in said manifold and a throttle valve anterior to said supercharger, a throttle control which comprises, in combination, a pilots lever,

metric element in said chamber, a first passage for connecting said chamber with said manifold posterior to said supercharger, a second passage for connecting said chamber with said manifold between said throttle valve and said supercharger, a relay device having a pilot member and a power member, an operative connection between said manometric element and said pilot member, means operative by said power member for altering the connection between said pilots lever and said throttle valve, and means operative by said power member for increasing the ratio between the cross sectional areas of said first and second passages as said power member moves in the direction of opening said throttle valve.

12. In connection with an internal combustion engine having an induction manifold, a device for controlling the amount of air or mixture supplied to the enginewhich comprises, in combination, a throttle valve in said manifold, a pilots lever, an operative connection between said pilots lever and said throttle valve, a variable datum boost control responsive to the pressure in said manifold, a relay device in said boost oontrol, a. power member in said relay device, means operative by said power member for varying the amount of air or mixture supplied to the engine through said manifold, and means operative by said power member for lowering the rated induction pressure as said power member moves in the direction of increasing the amount of air or mixture supplied to the engine'. 4

13. In connection with an internal combustion engine having an induction manifold, a device for controlling the amount of air or mixture supplied to the engine, which comprises, in combination, a throttle valve in said manifold, a Vpilots lever, an operative connection between said pilots lever and said throttle valve, a variable datum boost control, a chamber in said -boost control, a passage for connecting said chamber with said manifold, a manometric element in said chamber, a relay device having a pilot member and a power member, an operative connection between said manometric element and said pilot member, means operative by said power member for varying the amount of air or mixture supplied to the engine through said manifold, and

means operative by said power member for lowering the rated induction pressure as said power member moves in the direction of increasing the amount of air or mixture supplied to the engine.

14. In connection with an internal combustion engine havingr an induction manifold, a device for controlling the amount of air or mixture supplied to the engine, which comprises, in combination, a throttle valve in said manifold, a pilots lever, an operative connection between said pilots lever and said throttle valve, a `variable datum boost control, a chamber in said boost control, a passage for connecting said chamber with said manifold, a manometric element in said chamber, a relay device having a. pilot member and a power member, an operative connection between said manometric element and said pilot member, means operative by said power member for varying the amount of air or mixture supplied to the engine through said manifold, and means operative by said power member for increasing the length of said manometric element which corresponds to the inoperative position of said pilot member, as said :power member moves in the direction of increasing the amount oi air or mixture supplied to the engine.

15. In connection with an internal combustion engine having an inductionmanifold, a device for controlling the amount oi air or mixture supplied to the engine, which comprises, in combinai tion, a throttle valve in said manifold, a pilots lever, an operative connection between said pilots lever and said throttle valve, a variable datum boost control, a chamber in said boost control, a

passage for connecting said chamber with said manifold, a manometric element in said chamber, a relay device having a pilot member and a power member, means operative by said power member for varying the amount of air or mixture s upplied to the engine through said manifold, a floating lever, and operative connections lfrom three different points of said iloating lever respectively to said manometric element. said pilot member,

and said power member, said last mentioned opbination, a throttle valve in said manifold, al

pilots lever, an operative connection between said pilots lever and said throttle valve, a variable datum boost control, a chamber in said boost control, a passage for connecting said chamber with said manifold, a manometric element in said chamber, a relay device having a pilot member and a power member, an operative connection between said manometric element and said pilot member, means operative by said power member for varying the amount of air or mixture supplied to the engine through said manifold, means for imparting a load on said manometric element, and means operative by said power member Afor increasing the load on said manometric element as said power member moves in the direction oi increasing the amount of air or mixture supplied to the engine.

17; In connection with an internal combustion engine having an induction manifold, a device for controlling the amount of air or mixture supplied to the engine, which comprises. in combination, a throttle valve in said manifold, a pilots lever, an operative connection between said pilots lever and said throttle valve, a variable datum boost control, a chamber in said boost control, a passage for connecting said chamber with saidmanifold, a manometric element in said chamber, a relay device having a pilot member and a power member, an operative connection betweensaid manometric element and said pilot member, means operative by said power member for varying the amount of air or mixture supplied to the engine through said manifold, a spring for loading said manometric element, and means operative by said power member for increasing the strength of said spring as said power member moves in the direction of increasing the amount of air .or mixture supplied to the engine.

* REN Lozrvrr.

JOHANN HCI-I'IENS'I'EIN. PAUL XAVIER AUGUSTE, GISTUCCI. 

